Discharge of solubilized and Dectin-1-reactive β-glucan from macrophage cells phagocytizing insoluble β-glucan particles: Involvement of reactive oxygen species (ROS)-driven degradation

► Soluble β-glucan was detected in the medium of macrophages phagocytizing β-glucan particles. ► Soluble β-glucan discharged from macrophages activated the other macrophages. ► ROS-production inhibitors reduced soluble β-glucan discharge from the macrophages. ► Soluble β-glucan produced by in vitro ROS-driven degradation activated macrophages.